This invention relates to an optical apparatus and a method for reading information recorded in a magnetic recording medium utilizing interaction between light and magnetism.
In recent years, use of a vertical magnetic recording medium having a readily magnetizable axis in the direction perpendicular to the surface of a coating film has drawn attention of all concerned as a recording and reproducing system capable of optically reading information contained in the recording medium with super-high density.
This system is to read out recorded information by first illuminating with rectilinearly polarized light a vertical magnetization recording film where a magnetic domain having an upward magnetization with respect to the film surface and another magnetic domain having a downward magnetization thereto have been formed in correspondence to information to be recorded, and then detecting patterns of the abovementioned magnetic domains by use of a phenomenon where the polarized plane rotates depending on the direction of the magnetization, e.g., the magnetic Kerr effect or the Faraday effect.